They say ‘the key to a person’s heart is through their stomach’. Could it also be the key to their mood and mental health?

Detail of Microbial Mood by Sophia Charuhas (UK) during Science Gallery Melbourne's MENTAL season, (Alan Weedon, 2021)

Across the globe and closer to home at the University of Melbourne, researchers are investigating the gut-brain axis, aka the physical and biochemical communication between our digestive tract and brain.

The gastrointestinal tract—which runs all the way from the mouth to the large intestine—is often referred to as the ‘second brain’. It’s the only organ in the human body to have its own nervous system, made up of a network of millions of brain-like neurons wrapped in and around the gut.

Exhibiting now at Science Gallery Melbourne, ‘Microbial Mood’ is an exhibit by medical writer and bio artist, Sophia Charuhas. As the name suggests, the colonies of bacteria living in our digestive system can influence our mood.

In animal studies, changing the gut bacteria of mice eased anxious feelings and helped to control cortisol (stress hormone) levels in the blood.

In one human study, half the participants took a daily prebiotic supplement (which essentially acts as food for ‘good’ gut bacteria) while the other half took a placebo drug.

After three weeks, they were tested on their ability to process emotional information (such as positive and negative words). Those who took gut-friendly prebiotics were able to change the way they process emotional information, making it easier to ward off anxious or depressed feelings.

A similar effect can be seen in people who take prescription medication for depression and anxiety.

PhD candidate Matteo Pitteri writes that ‘good’ gut bacteria feed on fibre to produce essential fatty acids. Some high fibre foods include lentils, broccoli, avocadoes, berries, popcorn and nuts. Meanwhile, consuming high volumes of saturated fats and sugars inadvertently promotes ‘bad’ gut bacteria.

Dietary intake is important for our mental health because people with healthy and diverse gut microbiomes are less likely to be anxious or depressed.

But are food choices the only way we can encourage good gut bacteria to thrive? Step inside the speculative treatment room at Science Gallery Melbourne to find out.

There’s a lot left to learn about the gut-brain axis. What we do know is that humans are walking bacteria farms, so understanding the complex interactions between our gut and brain chemistry could help us to explore new kinds of treatment options for our mental health.

Part exhibition, part experiment, MENTAL is a welcoming place to confront societal bias and stereotypes about mental health. See ‘Microbial Mood’, now showing until 18 June.

A Deeper Look at Our Gut Feelings